1. Field of the Invention
The present invention relates to a robot having a force control function.
2. Description of the Related Art
Operations for assembling industrial products, such as automobiles and home appliances, have been performed manually, and automation of such an operation has been demanded. The operations that are generally manually performed include an operation of fitting a plurality of components to each other, a force-following operation (for example, an operation of pressing a component against another component at a certain force), etc., which require relatively delicate movements. In the case where a robot is caused to perform such operations in place of a human worker, it is necessary to accurately control a force (hereinafter referred to as an external force) applied by the robot to the components (workpieces) handled by the robot.
Japanese Patent No. 3383614 (Japanese Unexamined Patent Application Publication No. 2001-38673) discloses an example of a method for controlling a force applied by a robot. In this method, a contact sensor, such as a pressure-sensitive sensor, is attached to a surface of an arm of a robot. The external force applied to the arm is measured by the sensor, and a driving unit (actuator) of each joint of the robot is controlled on the basis of the result of the measurement. In addition, Japanese Unexamined Patent Application Publication No. 2008-307634 discloses a technique in which a six-axis force sensor is attached to a wrist of a robot. A force and a moment applied to a workpiece at a hand of the robot are determined, and a drive amount of each driving unit is controlled on the basis of the determined force and moment.